Louder sounds are perceived as having more bass and bias subjective comparisons.

Evidence

In any listening comparison louder sounds are perceptually recognizable which is an advantage for persons looking for a reason to express an opinion. Other things being equal, that sound would also have more perceived bass (the equal-loudness contours, Section 9.4). It is a well-known sales strategy. … Loudspeakers radiate distinctive three-dimensional sound fields into a reflective listening space, meaning that it is probably impossible to achieve perfect loudness equality for all possible elements (e.g. transient and sustained) of a musical program. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1122

Categorization

• XREF: Connects to equal-loudness contours and how level changes perceived spectral balance — relevant to audio engineering claims about loudness war in music mastering.
• CANDY: The ‘louder sounds have more perceived bass’ sales strategy is a fun, tweetable insight about why louder speakers impress in showrooms.